Certain energetic binders which are useful in propellants and explosives formulations are known in the art. By way of illustration, a compound called GAP (glycidyl azide polymer) is known to provide energy and function as a binder when formulated in propellants and explosives used in various applications. However, materials such as GAP are very expensive, costing up to $100 per pound and are known to release gases during storage and/or prior to or during processing. In addition, toxic and explosive ingredients are required to produce this polymer. Therefore, alternate high energy binders that are less expensive and safer to produce and still afford a good combination of desirable characteristics, such as a high impetus, a low glass transition temperature, and a low viscosity, would be highly desired by the propellant and explosives community.
Various nitropolymers have been fabricated in the past for application in solid, smokeless propellants. For example, Aerojet General published a report, Report No. 1162, dated Sept. 28, 1956, entitled "Research in Nitropolymers and Their Application to Solid Smokeless Propellants". This report documents various polymerization reactions useful in making nitropolymers, including various esters of nitramino diacids. These polymers, however, generally have a higher molecular weight than might be desired and do not possess carefully controlled, reactive, functional end groups as would be desirable.
Hercules Incorporated investigated a specific nitramine-containing polymer, poly(diethylene glycol-4,7-nitrazadecanedioate) designated as P-DEND. In a report entitled "High Performance Minimum Smoke Propellants", Technical Report CR-RD-PR-86-4, dated May, 1986. Hercules documents work performed for the U.S. Army Missile Command wherein P-DEND is described as being a feasible ingredient for use in nitrate ester-plasticide propellants. This report states that attempts to fabricate P-DEND by an acid catalyzed esterification reaction of 4,7-dinitrazadecanedioic acid (DNDA) with diethylene glycol in a variety of organic solvents were unsuccessful. This failure is attributed in the report to the fact that a cyclization reaction rather than a polymerization reaction occurred. More recently, the prsent inventors have found that P-DEND has a viscosity and a glass transition temperature that are higher than might be desired.
New polymer binders exhibiting excellent impetus and characterized by an advantageous viscosity and glass transition temperature would be highly desirable to the propellants and explosives community.